This invention relates to chain saws, and more particularly it deals with a chain saw receiving a supply of required lubricating oil for a saw chain in conformity with the sawing condition.
Generally, feeding of lubricant to a saw chain is not performed in conformity with a sawing condition but carried out substantially at a predetermined volume by utilizing the rotation of the internal combustion engine of the chain saw even in idling speed. In some cases where attention is paid to avoiding seizure of the saw chain, an additional supply of lubricant is made available by means of a manually operated pump.
Means for feeding lubricant, directly linked to the engine rotation, is not only unable to prevent dissipation of the lubricant during idling, but also unable to effect lubricant feeding in a rational manner to permit sawing operations with increased efficiency. Thus there has been a demand for means for performing lubricant feeding in a manner to increase the efficiency of sawing.